Tail light/Brake light puzzle

[jcraks]

I recently bought and installed a pair of new LED rear lights, with both tail and brake lights. Upon testing, it turned out the brake lights worked fine but the tail lights would not light when turning on head lights. I checked voltage to light and got 12 volts. Instead of buying new lights again, I bought 2 inexpensive trailer marker lights and mounted on back. I hooked them up and they worked fine. The puzzle is that when the head lights/tail lights are on, brake lights won’t light up. Any ideas? Please help.

[Wakko47]

If you individually power them up do they work properly? What kind of cart are you working with? Aftermarket or factory harness?

[meimk]

Were the old lights also LED, same brand? I have found that several manufacturers wire the LED lights in a different order (hot vs ground). I might not matter to an older incandescent light, but LED's ARE polarity sensitive. Try jumper wires to different arrangements of + and - inputs and see if they match up with what your wire harness is delivering and if both tail / brake functions are working correctly in your fixtures.

[jcraks]

I have a early 80s Club Car DS. I’m pretty positive it has original wiring. I did try to wire them individually, and the tail lights would turn on but the brake lights would not regardless if the head lights were on. The old lights were original bulb type. Should I just replace them with a new set of bulb lights?

[Wakko47]

We want you to test them off the cart. Make sure that the wiring is the same as the old ones, and that it actually has brake light capability.

[jcraks]

The lights have 3 wires, black, white, and red. Isn’t one for brake, one for tail, and one for ground?

[meimk]

Yes. Now test which wire in your cart's harness supplies tail light power (+), brake light power (+) and ground. Then test the light assembly with jumpers. The point is the order of the wires in your harness could very well be different than the order in your light assembly. Plus being LED they are polarity specific. You won't hurt anything running power through the wrong wires into the assembly, but they won't light that way.

[jcraks]

Harness wires are, brown for tail lights and yellow for brake lights. The LED lights have red,white, and black. Please explain how to use jumpers, I’ve never done that before.

[Wakko47]

Do you have any wires with alligator clips? Regular wire and tape will work in a pinch. Assuming that the black is ground: Simply connect one end of a wire to the negative 12 volt source. Attach the other end to the black wire/terminal on the light itself. Take a second wire and attach it to the positive 12 volt source (careful not to allow the two wires to touch). Take the end of that positive wire and touch it to each of the other terminals on the light itself (white and then red). Your lights should illuminate when you complete the circuit. Depending on the lights, either you'll have a set of dimmer LEDs that will light with one wire, then brighter LEDs with the other, OR all the LEDs will light with one and only half will light with the other.

If the lights work by hooking them up directly, then you know that the lights themselves aren't the problem.

[simicrintz]

Seems easiest to take a 12V battery out to the cart and test the lights that way, then figure out the cart harness from there. I would confirm that the lights work first before wiring them up.